A prospective, multicenter phase II trial of low-dose erlotinib as maintenance treatment after platinum doublet chemotherapy for advanced non-small cell lung cancer harboring EGFR mutation.

BACKGROUND: Maintenance therapy with full-dose erlotinib for patients with advanced non-small cell lung cancer (NSCLC) has demonstrated a significant overall survival (OS) benefit. However, 150 mg/day of erlotinib seems too toxic as maintenance therapy. This study aimed to evaluate the efficacy and safety of low-dose erlotinib (25 mg/day) as maintenance treatment after platinum doublet chemotherapy in NSCLC harboring epidermal growth factor receptor (EGFR) mutation.

METHODS: Activated EGFR-mutation-positive NSCLC patients who did not progress after first-line platinum-doublet chemotherapy, ≥20 and ≤85 years old, with performance status (PS) 0-3 were included in this study. Low-dose erlotinib (25 mg/day) was administered until disease progression. The primary endpoint was overall response rate (ORR). Secondary endpoints included progression-free survival (PFS), OS, and safety. The required sample size was 40 patients.

RESULTS: The study was stopped early, after achieving only 28% of planned enrollment, due to poor accrual. Between April 2011 and May 2014, 11 patients (male/female, 5/6; median age, 72 years; PS 0/1, 8/3; stage IV/relapse after surgery, 9/2; exon 19 deletions/L858R, 7/4) were enrolled and accessible in this study. Partial response (PR) was observed in 6 patients (56%). Median PFS was 14.9 months [95% confidence interval (CI), 2.7-27.1 months] and median OS was not calculable. Toxicities were generally mild. Only one patient developed grade 3 aspartate aminotransferase (AST)/alanine aminotransferase (ALT) elevation. Eight patients developed grade 1 skin rash. No treatment-related deaths were observed. Eight patients progressed, and recurrences included brain metastases (n=3), local recurrence (n=2), local recurrence plus brain metastasis (n=1), bone metastasis (n=1), and pulmonary metastasis (n=1).

CONCLUSIONS: The study was stopped early due to poor accrual. However, our study suggests that maintenance therapy with low-dose erlotinib might be useful and tolerable in selected NSCLC patients harboring EGFR mutation.